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I want to use a half-height mini PCIe to connect a communication module to my PCB.

For example: to use a board like the Raspberry Pi 4 compute module IO board with a WiFi expansion board.

Given that I can arrange enough space and heat dissipation is not an issue for using both of them, are there differences between them except for their dimensions?

Can I connect a Mini PCIE and afterwards replace it with a half-height one?

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2 Answers 2

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The two styles are electrically identical. Your only issue will be ensuring that you account for the different mounting screw locations between the two lengths.

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  • \$\begingroup\$ On electronicdesign.com/technologies/memory/article/21800840/…), it says that they are not the same. "Though desktop PCI Express supports up to 32 lanes, standard mPCIe cards use only one lane. (mpcie) also includes support for USB 2.0 signals (...). Additional pins reserved for SIM card signals make 3G/4G connectivity (...) through mPCIe." do I need to change the schematic if I want to add an LTE medem? \$\endgroup\$
    – metsik
    Apr 29, 2021 at 8:13
  • \$\begingroup\$ Mini PCIe contains a subset of full-size PCIe's features (i.e. it only supports an ×1 bus) plus support for a number of non-PCIe features (such as a USB-2.0 bus), all using a different connector and form factor. Full- and half-height mini PCIe share the same connector and electrical interface but have a different overall size (and different screw hole locations). As for using the non-PCIe features of mPCIe you'll need to read the (non-free) specs or refer to the datasheet (e.g. of the LTE modem you want to use). \$\endgroup\$ Apr 29, 2021 at 11:09
  • \$\begingroup\$ Hanjal , as I see in the following links, they are not the same. (pinouts.ru/Slots/pci_express_pinout.shtml) (pinoutguide.com/Slots/mini_pcie_pinout.shtml) the pinout is different (pin 1 on pcie is not pin 1 on mini pcie). Furthermore- the mini version contains more pins than the PCIe. mini pcei also does not have a 12v pin. \$\endgroup\$
    – metsik
    May 11, 2021 at 7:26
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As can be seen in the following links, they are not the same. (pinouts.ru/Slots/pci_express_pinout.shtml) (pinoutguide.com/Slots/mini_pcie_pinout.shtml) the pinout is different (pin 1 on pcie is not pin 1 on mini pcie). Furthermore- the mini version contains more pins than the PCIe. mini pcei also does not have a 12v pin.

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